(1) Field of the Invention
The present invention relates to a combined machine for punching and laser cutting of flat sheet metal.
(2) Description of Related Art
Combined machines for punching and laser cutting of flat sheet metals are long known solutions which add—to the undoubted efficiency of individual punching and laser cutting machines—the operating flexibility of the combination of the two processes, that is a single manipulation of the sheet metal with the laser cutting replacing punching tools of complex shape. Thereby, each of the two processes, punching and laser cutting, may be best used on the sheet metal itself to be processed according to the design geometry of the piece and of the available punches.
More general architecture for an individual punching machine is the one of a fixed punching press, equipped with a tool changing device, with the sheet to be processed mobile on a Cartesian plane (XY). Contrarily, the most widespread architecture for the individual laser machine is the one with the sheet to be processed fixed and the head mobile, although solutions with fixed laser head and mobile sheet, or hybrid solutions, exist.
Combined punching and laser cutting machines are any punching machines which accommodate a laser head and not vice versa. The result is that the combined machines are at least provided with a fixed punching head, with a laser cutting head, also fixed, and with a Cartesian manipulator for the movement of the sheet metal on the plane (XY). A machine of this type is represented and described for example in EP-0491747-B1.
Furthermore, combined machines are known which are equipped with a mobile laser cutting head which allows adding the advantage of the low inertia of the motion of the laser head with respect to the inertia of the movement of the sheet. Solutions exist for the mobility of the laser head on a single axis (y) or on two orthogonal axes (xy). Obviously, the mobility of the laser heads in a single direction (y) or in the two directions (xy) makes controlling the combined motion of the laser head and of the Cartesian manipulator (XY) of the sheet metal, complex.
Combined machines with a mobile laser cutting head in a single direction (y) are described in JP-2006088214-A, JP-2007038286-A and JP-2009018334-A. The first patent shows a laser cutting head with single-directional mobility (y) in direction parallel to the one of the manipulator (Y) of the sheet metal. The second patent modifies the mobility (y) of the laser head and the design of the manipulator (XY) so as to allow the transversal through cutting of a sheet metal without interfering with the manipulator itself and its grippers. Lastly, the third patent enhances the two previous ones by adding a mechanical solution which compensates for the thermal expansion of the control screw of the movement of the laser head.
A combined machine is also known with mobility (xy) of the laser head in addition to the mobility (XY) of the manipulator of the sheet metal.